Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Message-ID: <c29b2b0c-2b0c-f79c-9de5-58a67edd5c87@linaro.org>
Date:   Sat, 17 Jun 2023 19:42:29 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101
 Thunderbird/102.12.0
Subject: Re: [PATCH 2/3] dt-bindings: backlight: lm3630a: add entries to
 control boost frequency
Content-Language: en-US
To:     =?UTF-8?Q?Heiko_St=c3=bcbner?= <heiko@sntech.de>,
        Maximilian Weigand <mweigand2017@gmail.com>,
        Lee Jones <lee@kernel.org>,
        Daniel Thompson <daniel.thompson@linaro.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Helge Deller <deller@gmx.de>, Pavel Machek <pavel@ucw.cz>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>
Cc:     dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org,
        devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org,
        Maximilian Weigand <mweigand@mweigand.net>
References: <20230602-lm3630a_boost_frequency-v1-0-076472036d1a@mweigand.net>
 <20230602-lm3630a_boost_frequency-v1-2-076472036d1a@mweigand.net>
 <17576d81-a342-0b77-367a-eb9f2b97b734@linaro.org> <7491264.lOV4Wx5bFT@diego>
From:   Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
In-Reply-To: <7491264.lOV4Wx5bFT@diego>
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 17/06/2023 18:34, Heiko Stübner wrote:
> Am Samstag, 17. Juni 2023, 12:12:17 CEST schrieb Krzysztof Kozlowski:
>> On 14/06/2023 21:08, Maximilian Weigand wrote:
>>> From: Maximilian Weigand <mweigand@mweigand.net>
>>>
>>> Add 'ti,boost_use_1mhz' to switch between 500 kHz and 1 MHz boost
>>> converter switching frequency, and add 'ti,boost_frequency_shift' to
>>> activate a frequency shift to 560 kHz or 1.12 MHz, respectively.
>>>
>>> Signed-off-by: Maximilian Weigand <mweigand@mweigand.net>
>>> ---
>>>  .../bindings/leds/backlight/lm3630a-backlight.yaml           | 12 ++++++++++++
>>>  1 file changed, 12 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> index 3c9b4054ed9a..ef7ea0ad2d25 100644
>>> --- a/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> +++ b/Documentation/devicetree/bindings/leds/backlight/lm3630a-backlight.yaml
>>> @@ -33,6 +33,18 @@ properties:
>>>      description: GPIO to use to enable/disable the backlight (HWEN pin).
>>>      maxItems: 1
>>>  
>>> +  ti,boost_use_1mhz:
>>
>> No underscores in property names.
>>
>>> +    description: |
>>
>> Do not need '|' unless you need to preserve formatting.
>>
>>> +      If present, change the boost converter switching frequency from the
>>> +      default 500 kHz to 1 MHz. Refer to data sheet for hardware requirements.
>>> +    type: boolean
>>> +
>>> +  ti,boost_frequency_shift:
>>> +    description: |
>>> +      If present, change boost converter switching frequency from 500 kHz to
>>> +      560 kHz or from 1 Mhz to 1.12 Mhz, respectively.
>>
>> So just make it a property choosing the frequency, not bools, with
>> proper unit suffix.
> 
> i.e.
> ti,boost-frequency-hz = <x>;
> with x being 500000, 560000, 1000000, 1120000
> 
> with the driver failing when the frequency is not achievable
> with the two knobs of 1mhz and shift.

Yeah, with a default value (500000, I guess).

Best regards,
Krzysztof